Benefits
by Greyjoys
Summary: When eager curiosity turns into more. When 'friends with benefits' reaches its breaking point. When love overcomes lust. Casey and Derek both know these points. Very graphic. Rated M.
1. Chapter 1

_Hey everyone. This is my very first Life with Derek fic. I hope you all enjoy!_

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__The first time was out of curiosity._

Casey crossed her arms over her chest as she wracked her brain for a comeback to Derek's insult. She bit her bottom lip, deep in thought. "Well at least I _have_ a brain!" at last she countered, smirking victoriously.

Derek scoffed, "You're all book smarts, Princess," he stated, rolling his eyes and crossing his arms in a similar fashion to Casey.

"What is that suppose to mean?" she asked, deeply confused by his remark.

"Sure, you can pass a test. But if you were out in the real world with drugs, crime, and," he gave her a devilish look, "sex, you'd get eaten alive."

It was Casey's turn to roll her eyes. But as she did this, her gaze shifted away from the eyes of the person before her. "Whatever," she finished, walking away in thought. Honestly, Casey got what he was saying. She probably couldn't survive in the real world. She wasn't a quick witted and fast on her feet as Derek was.

Derek grinned brightly. He had won this round; victory was his. Shaking his head, he sprinted up the stairs and into his bedroom, where he casually laid down on his bed.

Casey lies on her bed, deep in self conflict. She again told herself he was right. But she was not one to give up. Casey MacDonald did _not_ give up on learning anything. Even if took drastic measures. The part of what he said that got to her the most was the part about sex; an experience she had never felt. It made her feel hopelessly uneducated thinking about the world of sexual intercourse. Sure, she had thought about it, but never got around to experimenting with it. Why would she? She had good grades, had friends, and had her fair share of boyfriends. Why would she ever need sex? It would probably ruin everything anyway.

Still, as much as Casey tried to convince herself she didn't need to have sex with someone to know the ways of the streets; she couldn't get the thought out of her head. It was actually starting to embarrass her, so her cheeks were bright red. She suddenly felt like a perverted 10 year old who overheard her older sister talking about it. Finally she couldn't stand it anymore. She needed to be educated what was so great about the sexual experience. A smirked crawled across her lips as she figured who could give her that. _Why don't I learn from the best?_ she asked herself. With that she exited her room and sauntered down the hall.

An uneasy feel crept into the pit of Casey's stomach as she opened Derek's door. Was she really doing this? Was she about to give up so much? Was this a smart decision? All her thoughts vanished when she entered Derek's room.

Derek looked at Casey with a quizzical expression. Had he let her in and already forgot? Of course he didn't! "Come...in?" he dragged out, still looking at her. She was breathing in and out rapidly and clenching her fists. Without a word, she stood at the foot of his bed. Casey took in one last deep breath and stared Derek directly in the eyes.

"You're right. I don't know about street smarts," she stated, grabbing the hem of her shirt, "So..." she pulled the shirt over her head, exposing her light pink polka-dotted bra. Derek's eyes bugged out and became the size of quarters. "So, teach me," Casey said, dropping her shirt on his floor.

"What...?" Derek asked his eyes still wide. He backed up on his bed as she kept looking him in eyes, her face blank.

"Teach me," she instructed once again, kneeling onto his bed. A million thoughts raced through each of the teen's heads. Casey was scared and timorous; Derek was confused and nervous. Casey crawled down his bed until her lips were hovering over his. Derek balled his sheets up in his fists, realizing he couldn't back up anymore. "Teach me," Casey sighed, before capturing his lips in a passionate kiss.

A spark of electricity shot through Derek's entire body feeling Casey's lips on his. They were so soft yet dripping with lust. Before he could pull away, he was running his tongue over her delious lips. She nodded slightly and parted them, allowing him entrance. A moan escaped her when she felt his sweet tongue over her own.

Casey could no longer stand it, feeling herself wettening under his grasp; she ran her hands under his shirt and slowly lifted. Derek had lost all sense of judgment in his undying want for Casey. He helped her ease his shirt off over his head. The feeling of her hands roaming over his abs and chest her extremely mind-blowing for Derek. He carefully flipped them over so he was on top, not being one to enjoy the bottom.

Now he had his control over her. He let his hands rest on her stomach as he let his lips travel down to her collarbone. Kissing it gently, Derek's hands slid to her sides. Yet another moan came from the petite brunette. He kissed her deeply and began fiddling with the zipper of her jeans.

Casey felt overwhelmed as he slid her pants down and revealed her panties that matched her bra. Derek hovered over her, inspecting ever inch of her body. A traitorous groan came from him as he drown himself in her beauty. Trying to skew away from any sudden silences and loss of heat, Casey began removing Derek's jeans. They slid off with little struggle, showing off his green plaid boxers. She blissfully gasped when she saw how hard he was.

Derek couldn't believe he, Derek Venturi was there lingering over Casey MacDonald in his boxers. The thought passed as he was drawn in by her gorgeous body once again. He kissed her gently and stared right into her twinkling eyes.

"Are you sure you want this?" he asked, short of breath. A quick nod was the response from the girl below him. He too nodded and continued by pulling down her panties. He stared gazed lovingly upon her damp area. He quickly ran his fingers over it, trying not to be too forward. Again he looked up at her and she smiled weakly, clearly as apprehensive as him.

Once Derek knew Casey was ready he slowly removed his boxers. A furious blush spread across his face as she noticed his hardness. He took a deep breath and looked back up.

"This is going to hurt most likely," he said, knowledgably.

"I can take it," Casey tried to sound strong even though she felt like passing out. Though she said this, Derek still wrapped her arms around him, directing her nails at his back. With that he slowly entered her, not fully. Kissing her neck to distract her, he pulled out and pushed back in.

A pain flooded Casey's body and she dug her nails into Derek's back. She screamed loudly, the pain nearly unbearable. He still kissed her neck, but soon looked up at her. A stray tear rolled down her cheek as he stared concerned and loving at her.

"Do you want me to stop?" he asked, concerned. Casey shook her head and he thumbed away the tear. A long silence flooded the room as Casey let the pain ease, yet still enjoying the feeling of Derek filling her completely. Finally the pain was duller and she signaled to continue.

Derek pushed in at an even paced and heard another gasp come from Casey. He kept the even pace, kissing her every couple seconds to shoo away any pain she felt. Finally he could feel himself at his brink, causing him to look up at Casey. She was gasping and moaning frantically. He felt her walls closing around him and then she came. He pulled out of her before coming on his bed.

Casey couldn't stop her erratic breaths from coming. The feeling she had just witnessed was like nothing other. Yes she was still sore from the pain, but the pleasure that had overcome her was even greater. Glancing once at Derek, she noticed he looked equally as awestruck. Suddenly he sprung up and yanked on his boxers. Casey sat up in her elbows looking at him. He turned his back to her and she could see blood streaks and nail marks all over his back.

"You're bleeding," she stated, worriedly. He looked back at her and nodded as he pulled on his shirt. She cautiously put on her panties and groped for her jeans. Once she found them, she put them on as well. Standing, Casey looked Derek in the eyes. Though the exchange was perfect for words, both teens looked down in search for Casey's shirt. Derek was the first to grab it and hand it to Casey. She pulled it on and looked back at him.

Then, in a blink, she was out of the room.

_How was that for the first chapter? Feedback is wanted._


	2. Chapter 2

_I'm uber sorry I haven't updated in forever. Ya know school and shit like that. _

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_The second time was an escape_

Casey could hear her sniffles as she read her novel. It was a peaceful romance, something that always teared her up. She wished she had a man in her life to be that caring. Closing the book, she sighed and stared at her door. Tears were streaming down her cheeks, but she did wipe them away. She just stared at the wooden door.

A faint knock was heard on it. It had to be Derek. He was the only one home with her. Everyone else had gone out. They were left at home alone.

The door cracked open and Derek stuck his head in. Casey did bother to wipe her tears away, knowing he had already seen her cry and so much more of her. His faced shifted to a concerned looked. He opened the door all the way and walked into the room, closing the door behind him.

"You're crying," he stated, obviously. Casey turned her head and looked away. The remark was so stupid but sweet. He sounded so concerned that she was hurting.

"Yeah," she mumbled wiping her cheeks. Derek walked further into the room and sat on the edge of her bed. She turned her head back and their eyes met in a deep stare. Derek raised his hand and thumbed away a betraying tear. Casey looked down, staring at his lips. She was so eager to feel them on hers again. Ever since their experience, all Casey could think of wanting more. And how he pushed her out right after. Both confused her so much.

Derek got the subtle message and kissed her passionately. Casey ate up the kiss, but soon he pulled away. She just stared at him.

"I'm sorry..." he breathed. Casey shook her head and put both on her hands on his cheeks and kissed him with the same amount of passion. The kiss deepened quickly with tongues battling and soon Derek was lying on top of Casey. They broke their kiss and Casey smiled at Derek. He smiled back once he knew what he was doing was okay.

"How far do you want to go with this?" he asked, caringly.

"I don't care. Wherever you want to take me."

Derek answered by kissing her again. This time he could feel her hands wandering under his shirt, feeling his chest. He removed it and shivered as her hands traveled everywhere. Casey took off her own shirt, her bra coming off with it. Derek's eyes widened as he saw her full sized breasts, loving that he was seeing a new part of her body. He placed his hands on them and she gasped. It did feel right to give them any other treatment, so he went on removing his own jeans.

Casey could feel herself nearly leaping out of her skin. She wasn't as terrified with this as she was the last time, but it was still a thrill ride. She unzipped her jeans and slid them down, raveling her silk black thong. Derek raised an eyebrow at her, and she slapped him playfully. He then continued by kissing her neck, desperately wanting to mark her, claiming her his. But he couldn't do that. They were strictly friends with benefits. Nothing more. Nothing less.

Casey slid her fingers under the elastic of Derek's boxers and removed them carefully. This time he was not fully erect, but halfway. She grinned slyly and wrapped her had around his shaft. Derek moaned loudly as she pumped her hand up and down his cock.

"Casey…I...I..." he breathed and Casey removed her hand. She yanked down her thong. Her pussy was extremely wet. Derek chuckled and lowered himself He was ready to try something new. He gently kissed it and then licked her folds. Casey couldn't stop the uncontrollable gasps and moans from coming for her. Finally he came in his mouth. He drank up all her fluids and then kissed her, letting her taste herself.

"Fuck Derek..." she whimpered. He angled himself over her pussy and after a second, thrust into her, this time going all the way in on his first. The pain wasn't as great as before for Casey. IT was still there, but only dull. It didn't take as long for the pleasure to kick in.

Derek kept thrusting into her carefully and slowly. He still didn't want to hurt her. Also, his emotions were trying to overthrow him, and he couldn't have that.

"Shit Derek...harder...faster..." Casey moaned loudly, craving more of him. He did as told and pumped harder into her. After a few seconds he felt her walls tighten around his dick. She had hit her orgasm.

"Oh my God! Derek!" she cried and came. He then hit his too.

"Casey..." he moaned, and pulled out. They lay there next to each other, this time he didn't rush away. He just laid there, trying to get himself on track. He glanced over at Casey who was breathing in and out erratically. That was when the door opened and closed downstairs. Neither of the teens moved.


	3. Chapter 3

_Okay, I realize the end of the last chapter was like a cliffhanger, but I'm not continuing with that. It was just supposed to be an end. Enjoy the new chapter!_

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_The third time was when the passion took over_

Casey laid on the couch, flipping through the channels on the TV. There was, officially, nothing to watch. None of her soap operas, the ones Derek constantly mocked her for watching, were on. The only thing on was sports. She had thought Derek would be camped out in front of the TV by now. He was probably still asleep, or at least she assumed.

Once again, they were left alone at home. There parents were giving them their independence, which both teens thought they deserved. But them being alone meant Casey bored out of her mind and Derek sleeping until 3 in the afternoon.

"Hey," an enthusiastic voice popped up behind Casey. She had heard the thumping down the stairs, but didn't expect Derek to be so jumpy.

"You're awake?" Casey asked, sitting up on the couch so she could see him. He nodded, energetically.

"Have been for hours," he told her, grinning charmingly. That was what Casey hated about Derek. Sure, they had had sex twice, but it was strictly 'Friends with benefits'. And oh did it have its benefits. But as much as Casey told herself it was nothing more, she was never completely convinced. Then, she would finally start believing it and that she didn't have feelings for Derek. But not long after would he come and show her his amazing, sweet, loving, charming self that she had grown to like. Maybe even love.

She shook any thoughts of her thinking of Derek and love in the same sentence. She didn't love Derek. He was an ass. He made new ways to be a douche bag. Those were the things she loved to hate about him. But also, hated to love.

"Wow, Derek Venturi got up before 3, stop the presses!" she said sarcastically. Derek shook his head at the insult and jumped over the couch, sitting on the opposite side from the brunette.

"What's on?" he questioned.

"Besides sports...nothing."

"Ooh, sports," he yanked the remote away from the girl and changed it to hockey. Her mouth stood agape while he watched intently. She groaned and rolled her eyes, staring at the TV reluctantly. Little did she know that now Derek had directed his eyes on her.

He was engrossed in the way she chewed on her bottom lip when she was annoyed. Oh how much he longed to be the one doing that to her. His eyes traced the shape of her body, taking in her beauty. It was true. He thought Casey was beautiful. He would admit it to anyone, but her. He felt ashamed to think about sweet, naive Casey the way he did. He felt disgusted that he had taken something so genuine from her. That was why he pushed her away after the first time. It had finally hit him that he had taken something from Casey that she could never get back.

Derek concentrated his eyes on something else. Anything else. They darted directly to a string on Casey's shoulder. It might've still been on her, but at least it took away his dirty thoughts. But soon the string started to annoy him. It was just sitting happily on her shoulder, unknown to the brunette. He was dying to brush it away, just for the principle of touching her.

Finally, he couldn't contain himself anymore. He leaned over and dusted the string off her shoulder, his knuckles grazing her hair lightly. She looked over at him and smiled.

"Thanks...I guess," she thanked awkwardly. Derek breathed inwardly and decided to strike up a question.

"Can I...well may I," he didn't want to be grilled for his grammar when asking Casey something important, "kiss you?" Casey nodded and waited for his soft lips to cover hers. First, she made sure the door was locked, just in case, and then looked back at Derek expectantly.

He leaned in ever so gently and softly placed his lips on hers. The feeling was more amazing then every other time he had earned to pleasure of kissing the gorgeous girl. They both pulled away and Casey stared into his eyes. So deep and pure. All she wanted to do was kiss him forever. She knew she could.

Scooting closer to the boy next to her, Casey wrapped her arms around Derek's neck. He smiled, placing his hands on her waist. She kissed him this time and let the kiss stay simple for a few seconds, before opening her mouth slightly. Derek let his tongue slowly slip into Casey's expecting mouth. She pushed herself closer to his body, feeling a need for the boy. She ran her tongue over his and wrestled for dominance. But in the end, Derek won. Like always.

He carefully pushed her back, lying on top of her. Casey brought her hands down and let them rest on his broad shoulders. She was in love with the kiss that was going on. It was so skillful. So gentle. So loving yet passionate.

"Can we...?" she breathed, pulling away from his kiss. He rested his forehead on hers and nodded.

"Only if you want to."

"I do," she told him. He kissed her once again and moved his lips down her jaw to her neck. This time his hunger to leave his mark of territory was almost painful. He still found the strength to pull away. Derek distracted himself by unbuttoning the first three buttons on her shirt. When he was done, the opening revealed her white bra. How he envied the piece of clothing for getting to hug onto her body all the time. Derek glanced up and his eyes met Casey's. She was smiling bright, motioning for him to go further. He undid the rest of the buttons and pulled off her shirt, exposing her stomach. He trailed kisses down chest and stomach, leading to her jeans.

Casey let her hands wander up the boy's shirt and pulled it off, showing off each detailed muscle. Suddenly, she felt protected, seeing his body. She grabbed his cheeks and pulled him into another kiss.

Derek was careful, undoing the button of her jeans. He unzipped them and pulled them, showing off the pair of boy-short underwear she had chosen to wear. He didn't care what they were; he thought she'd look beautiful in anything and everything. How he wished to tell her that.

The brunette girl smiled and removed Derek's jeans as well. She wrapped her arms around his neck again, waiting for him to choose his next choice of clothing to take off of her. He chose her boy-shorts. When he pulled them down, he moaned seeing her pussy. He loved the look of it so much. So beautiful. So natural.

Casey eased off Derek's boxers, revealing his erection. She was surprised it was full. This had been their least passionate session, but yet he was still so hard for her.

"Please...start," she moaned out, feeling herself getting more and more wet as she stared at his erection. He nodded in agreement and pushed himself softly into her. He loved the familiar warm, wet feeling of her pussy.

Casey felt no pain, but just the pure pleasure of him filling her entirely. Derek pumped in and out of her so softly, but this time Casey didn't yearn for anything more. She just wanted him to stay inside as long as possible.

Derek could feel himself just on the edge. That was when he felt her walls closed around him and her hips started bucking against his. That sent him over the edge. His orgasm was quiet, as well as Casey. He felt himself cum inside of her, and then pulled out.

Casey couldn't believe how unbelievably casual it was. It was so loving. So careful. She pulled herself out from under him and pulled on her boy-shorts, as well as her jeans and shirt. Derek too started getting dressed, not bothering to put his shirt on. He laid down where Casey had been, letting her button up her shirt.

When she turned around she saw he had taken her spot. She sat on the other side, lifting his legs up. She noticed the hockey game was still on.

"I have no clue what's going on," she started conversation. "Can you maybe explain it to me?"

Derek raised an eyebrow, "Sure."

"Wait," Casey stopped him while he was taking a breath. She crawled up his legs and rested her head on his chest, laying on him. Derek smiled and kissed the top of her head while she settled her head on his chest. He placed a hand on the small of her back, and started explaining when she was ready.


	4. Chapter 4

_The fourth time was spontaneous_

"No…" Casey said firmly as she was pressed against the sink in the upstairs bathroom by none other than Derek, "Everyone's downstairs!"

He chuckled and proceeded kissing her neck ever so lightly. "That's while we'll have to make it fast," he smirked, placing a kiss on her lips. Casey felt herself slowly melting into it until she felt two large hands running under her blouse and up and down her sides.

"_Der-ek!"_ she whined, pulling her lips out of reach. Despite her protest, her step-brother wouldn't budge. He latched his taunting lips to her neck for another time, sucking on her pulse point ruggedly.

The girl couldn't help it. She knew there was no way he would give in and just go back downstairs. And she was now slightly turned on, feeling the warmth of his hands grazing over her stomach.

She pushed him back a bit and lifted her top over her head. They didn't have time for the teasing and such. They needed to be quick; the faster it was over, the better she'd feel.

Derek raised an eyebrow, looking at the familiar body before him. Casey had given in way easier than usual. She was so reluctant to anything having to do with him that he thought that he'd have to yank her clothes off of her. He snickered and leered forward, covering the skin above her right breast with his lips.

Casey felt her senses collapsing while he bit and teased her chest. She could only remembered the objective and pulled his head up to hers, kissing him deeply. She had to remind him of what needed to be accomplished. He returned the kiss in a way of saying "I've got this."

His nimble fingers trailed down her stomach, reaching the waist of her jeans. He ran his fingers under the band before holding the button in his hand. He slipped it out of its hole and continued to the zip. He didn't hesitate to pull it down quickly.

She kicked her jeans off, discarding them far away. There she stood, in just her bra and panties. The surprising thing was that she no longer felt any twinge of embarrassment being almost naked in front of him. She honestly felt beautiful, that someone wanted to see her like this.

Derek worked his jeans off and reattached himself to the girl. When she was like this, he found it hard to keep his hands off of her. She was gorgeous and he wanted her to know he thought that.

Soon, her panties were shed and pooled around her ankles. He ran his fingers up her thigh, reveling in the way she shuddered under his touch. He finally reached her center. He swept his fingers up her slit, feeling the moisture gathering there. She had to grip the counter as if not to fall over.

His boxers were taken off and he slowly took her leg and wrapped it around his waist, to give access to an easier entrance. Casey gripped his shoulder tightly and closed her eyes. He turned his head to kiss her temple before ever so slowly sliding into her.

She felt a small pain and adjusted herself better. It was much better than the first time, but was still there. She squeezed his shoulder to signal that she was ready. He started moving at a slow rhythm like always. He never wanted to hurt her, and would wait as long as she needed to make sure she was ready.

Their movements eventually became more and more fervent. Casey felt herself reaching her peak. She threw her head backwards and climaxed, her body shaking with pleasure. Derek shortly came after, leaning his head against her chest, mumbling her name.

After recovering, they detached and pulled their clothes back on. Both grinned at each other.

"That was awesome," Derek complimented and kissed Casey on the lips gently. She kissed back and then pulled back.

"It was…" she headed towards the door but he caught her wrist, bringing her back for yet another kiss. She smiled into it. "We have to go back downstairs."

He nodded and they left the room, both elated.


End file.
